Available at the Benefit booth at Myer stores, so that would be all the CBD locations.
EDIT: This is available at all Myers with Benefit booths, not just CBD.
You must ask for the "Wing it on tutorial" to receive your free samples. It takes 3 minutes and demonstrates the use of the They're Real Gel Eyeliner.
Sample sizes are quite substantial.
They're Real Mascara sample: 3.0g
Full size: 8.5g, $38
You get ~$13.41 for free
They're Real push-up liner sample: 0.1g
Full size: 1.4g, $35
You get ~$2.50 for free.
If you like brand name makeup but don't want to pay for it, this might be a good time to Broden it. Mascaras are recommended to be thrown away every 6 months to reduce chance of eye infection, so getting a bunch of small sample sizes means you use it up in 6 months and never throw away unused products. The official retail "Travel size Mini" of the They're Real mascara sold by Benefit is $15 and 4g, so the freebies are a nice deal.
WHILE SUPPLIES LAST.
EDIT: Went to Myer Sydney CBD again, and they asked for a signup to their email newsletter before commencing the tutorial. Use a fake/burner email if you do this, but they might not ask you if you go during a busy time. The sales rep opened a drawer to fetch the samples, and I eyed about 40 of each still in there. Myer Sydney City has 2 Benefit booths, the regular one and the Brow Bar, which both have supplies of the sample and do the tutorials. I would guess there's probably 100 sample sets left altogether, so don't wait till the last minute to get yours. Or else the Brodens will get them. ;)